Antenna theory

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Figure 3.

E and H plane radiation patterns

1.1.3

Field regions

Various parts of a radiation pattern are referred to as lobes, which may be sub-classified into

major or main, minor, side and back lobes.

A radiation lobe is a portion of the radiation pattern bounded by regions of relatively weak

radiation intensity. Figure 4 demonstrates a symmetrical three-dimensional polar pattern

with a number of radiation lobes.

A major lobe (also called main beam) is defined as the radiation lobe containing the

direction of maximum radiation.

A minor lobe is any lobe except the major lobe. Minor lobes usually represent radiation in

undesired directions and they should be minimized.

The beamwidth is the angle, expressed in degrees, between the half power (-3 dB) points of

the main lobe, when referenced to the peak effective radiated power of the main lobe.

Figure 4.

Field regions

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